Sampling device



NOV. 13, 1945. ROETMAN 2,388,801

SAMPLINQ DEVICE Filed Ap ril 1, 1942 INVENTOR. EDMUND .7. FUETMH/v B j)l k ATTORNE? Patented Nov. 13, 1945 ill" nnvrcn application April 1,1942, Serial No. 437,141

4 Claims.

This invention relates to a device for sampling flowing liquids,particularly for operation with streams of industrial wastes todetermine the presence of recoverable values of constituents therein.

It is an object of the invention to provide a sampling device forobtaining a representative sample of the liquid over a period of timewhether the flow of liquid during said period has been constant or hasvaried with respect to quantity and/or analysis. Accordingly,the-deviceof the invention is constructed to obtain an individual sample thevolume of which is proportional to the rate of flow of the liquid beingsampled and the device is so operated as to repeatedly take suchindividual samples at equal intervals of time. The device of theinvention is simple in construction and is substantially free of anytendency to gather or to be clogged by suspended matter, particularlyhbrous material, which may be present in the stream being sampled. Otherobjects, features and advantages of the invention will be apparent fromthe drawing and the description thereof hereinafter.

In the drawing, illustrative of the invention,

Figure l is an elevation of the device arranged in a measuring fiumeshown in cross-section,

Figure 2 is a side elevation of the device of Figure Figure 3 is a viewlooking head-on at the sampling spoon of Figure 2, and

Figure a is a similar view of a modified shape v of sampling spoon.

As shown in Figures 1 and 2, the sampling device is associated with aParshall measuring fiume 2, the upstream end of which is shown just tothe downstream side of the sampling device. This measuring fiume is ofstandard construction and comprises a floor 3 and two side walls 5 whichare joined to the floor 5 and side walls 6 of the channel proper bysuitably sloped sections l.

The sampling device proper comprises a dipper d having a scoop e whosehandle it is in the form of a trough which serves to direct the liquidto a short transverse trough ii communicating therewith. This transversetrough is provided with an opening 82 at the heel: which, allows theliquid to pour from the dipper 8 and trough it into a catch-box 53secured therebeneath on one of the side walls 6 of the channel. Thedipper is-fastened along its transverse trough portion H to a shaft itwhich is suitably mounted for rotation about an axis transverse of thechannel. This shaft it is provided with a sprocket i5 which is driven bya chain is operated by the sprocket H on the shaft of the motor it. Thescoop 9 is preferably rotated in the direction of flow so that anymaterial of a fibrous nature caught upon it is washed ofi during itsnext dipping stroke. The catch basin is provided with a discharge pipeconnection it which leads the samples to a suitable receptacle in whichthey may be allowed to accumulate for the desired length of time beforeanalysis.

The shape of the dipper 8 is readily apparent from Figure 3 which is itsappearance as seen by an observer looking upstream at the device inFigure 2. While the scoop portion Q of the dipper is formed with itsside edges 2% (see Fi ure 2) horizontal when they are in alignment withthe level of liquid at its maximum expected head, this is not absolutelyessential but merely makes the calculation of the other dimensions ofthe scoop somewhat simpler than would otherwise be the case. Similarly,the sides it of the scoop portion of the dipper need not be parallelsince suitable adjustment of other dimensions of the scoop permit othercross-sectional shapes of the scoop to be used, such as that shown inFigure 4 where the sides 2i slope inwardly from the top to the bottom ofthe scoop.

.The particular shape and relation of the scoop and handle id of thedipper shown in Figures 1 and 2 were designed for a stream whose maximumliquid head would be about 6 inches below the center line of therotating shaft which is about 18 inches above the elevated floor of themeasuring iiume. The angle 0: is about the extreme lip ii of the dipperis 18 inches from the center line of the shaft so that no sample isobtained when the liquid does not exceed the level of the elevated floorof the measuring fiume.

lhe bottom of the scoop Q is a continuation of the bottom of the troughhandle Eli and is in the form of a circle having a three-inch radiuscen= tered along the line from the center line of the rotating shaft tothe extreme tip of the scoop 9. The length of the sides of the scoop isof the order of the radius of the curved bottom. All of these dimensionsare selected to give a quantity of sample proportional to the head ofthe liquid at the instant of sampling when the device is employed with ameasuring fiume whose characteristic equation is Q=kH It will be readilyappreciated that the various dimensions just cited which yield actualsamples which are within 1% of the theoretical amount desired may bevaried and adjusted as desired to give numerous shapes and sizes capableof giving an amount of sample in direct proportion to the head of liquidflowing. For example, a further refinement with a consequent reductionin the percentage of error ,i-ust cited may be obtained merely bybuilding up a small portion of the inner curved surface of the scoop 9to flatten it along about a. one-half inch are approximately one inchfrom the extreme lip 2| of the scoop.

The device may be employed with any measuring device, such as ameasuring fiume or weir in which the quantity of liquid flowing isproportional to some exponential function of the head of liquid in thechannel, the shape of the scoop being changed to yield the appropriatesample with different exponential function of the head.

The sampling device of the invention has all of its operating mechanismoutside the stream being sampled and is of relatively simpleconstruction so that there is no clogging of the device or gathering offoreign matter on it. On this account, it is particularly satisfactorywhen employed for sampling waste liquids, solutions, and

suspensions containing fibrous material, such as occur in all industriesdealing with paper pulp or the manufacture of products, such asartiflcial filaments, therefrom. In the claims the expression "liquid isintended to include simple liquids, solutions, dispersions, suspensions,and the like.

While preferred embodiments of the invention have been disclosed, it isto be understood that changes and variations may be made withoutdeparting from the spirit and scope of the invention as defined by theappended claims.

I claim:

1. In combination, a channel, a liquid-measuring device for maintaininga definite relation between the height of liquid in the upstream side ofthe measuring device and the volumetric rate of flow thereof through thechannel, a unitary dipper member comprising an arm terminating in ascoop having an open face to allow entrance of the liquid, means forswinging the scoop in a single direction through a cyclical path atconstant frequency, the swinging means being so arranged with respect tothe channel that the scoop in a portion of its path moves face-firstdown into, and then up out of, the channel adjacent the upstream side ofsaid measuring device in a direction with the liquid current about anaxis transverse of the channel, and a conduit formed in the arm andassociated with the scoop for emptying it during a subsequent portion ofits path of any liquid it receives during that portion in which it isswung down into the channel. 2. In apparatus for sampling a liquidflowing in a channel, a channel, a liquid-measuring device formaintaining a definite relation between the height of liquid on theupstream side of the measuring device and the volumetric rate ofnowthereof through the channel, a rotatable shaft having an axis transverseof the channel and above the liquid surface therein, a scoop having anopen face to allow entrance of the liquid carried by the shaft forrotation therewith, a. conduit communicating with the scoop having anoutlet offset from the plane of rotation of the scoop, a receptaclebeneath the outlet, and means for continuously rotating the shaft atsubstantially constant speed to swing the scoop face-first through aportion of the channel in a direction with'the liquid current.

3. In apparatus for sampling a liquid flowing in a channel, a rotatableshaft having an axis transverse of the channel and above the liquidsurface therein, a scoop having an open face to allow entrance. of theliquid carried by the shaft for rotation therewith, means locateddownstream from the shaft for maintaining a definite relation betweenthe height of liquid in the vicinity of the shaft and the volumetricrate of flow thereof through the channel, a conduit communicating withthe scoop having an outlet adjacent the shaft and offset from the planeof rotation of the scoop, a receptacle beneath the outlet, and means forcontinuously rotating the shaft at substantially constant speed to swingthe scoop facefirst through a portion of the channel in a direction withthe liquid current.

4. In combination, a channel, liquid-measuring means associated with thechannel for maintaining a definite relation between the height of liquidadjacent the upstream side of the measuring means and the volumetricrate of flow thereof through the channel, said means having a floorelevated with respect to that of the channel adjacent the upstream sidethereof, a unitary dipper member comprising an arm terminating in ascoop having an open face to allow entrance of the liquid, means forcontinuously rotating the member in a single direction through acyclical path at substantially constant speed to swing the scoop in aportion of its path face-first down into, and then up out of, thechannel adjacent the upstream side of the measuring means in a directionwith the liquid current about an axis transverse of the channel, themember being constructed and arranged so that its axis of rotation isabove the maximum expected liquid level and the deepestimmersion of thescoop corresponds substantially to the floor level of the measuringmeans and so that it picks up an amount of liquid which is proportionaltothe height of liquid, and a conduit associated with the scoop foremptying it during a subsequent portion of its path of any liquid itreceives during that portion in which it swings down into the channel.

EDMOND T. ROETMAN.

